AMSTERDAM Recent European guidelines classifying actinic keratoses as in situ squamous cell carcinoma came under fire in a panel discussion at the 11th World Congress on Cancers of the Skin.
"Since our histopathologist started calling AKs carcinoma in situ I've had four patients in my outpatient clinic crying because they were given the diagnosis of cancer. They had to wait 3 weeks for a follow-up appointment to have somebody explain the situation to them, and it was 3 weeks of hell. They were afraid of dying. So I think from the patient's point of view this classification is a big mistake," said Dr. Alexis Sidoroff of the Medical University of Innsbruck (Austria).
Dr. Eggert Stockfleth, lead author of the published guidelines (Eur. J. Dermatol. 2006;16:599606) developed by the European Dermatology Forum and accepted by the Union of European Medical Specialists, defended the classification scheme on the basis of the histopathologic changes and genetic mutations shared by actinic keratoses (AKs) and squamous cell carcinomas (SCCs).
"Actinic keratosis is an early stage of cancer. It is not a precursor lesion," declared Dr. Stockfleth, director of the skin cancer clinic at Charité University Hospital, Berlin.
With the incidence of nonmelanoma skin cancer climbing worldwide by 7%10% per year, the guidelines committee felt that routine treatment of AKs is warranted to combat the problem, he said.
Dr. Irene Leigh, however, argued that categorizing AKs as carcinoma in situ implies an inevitability of progression that bears no relation to reality. The chance that any individual AK will transform into invasive SCC is extremely low, so it is better to view AKs as markers of increased risk of SCC. These AKs arise and often regress in a field of sun-damaged, dysplastic skin that is undergoing a process called field cancerization or simply field change, out of which most SCCs arise, she said.
"I don't call these lesions carcinoma in situ. I call them AKs. I don't think every AK is going to progress to squamous cell carcinoma. There's evidence for regression of AKs, and there's not much evidence for anything else," said Dr. Leigh of the University of Dundee (Scotland).
Dr. Hywel Williams expanded on this theme. "We are dealing with a field change. Surely what we see physically is like mushrooms in a mycelium of squamous metaplasia. The mushrooms pop up and others go down. To me, the idea that by freezing or otherwise treating a single lesion of AK we're dealing with the problem seems delusional," said Dr. Williams, professor of dermatology at the University of Nottingham (England).
"We are still in 2007 deluding ourselves about the value of destructive therapies for visible lesions and playing into the agenda of an enormous industry with vested interest in maintaining this ritual that we have," he added at the congress cosponsored by the Skin Cancer Foundation and Erasmus University, Rotterdam, the Netherlands.
Dr. Jean-Jacques Grob agreed that the case for routinely treating AKs to prevent SCC is weak in immunocompetent patients. Nor is there any persuasive evidence as yet that invasive SCCs can be prevented by treating the field cancerization process itself, although clinical trials involving imiquimod, photodynamic therapy, and other treatments are ongoing, noted Dr. Grob, professor of dermatology at the University of Marseille (France).
"Let's face it, aside from a few studies showing regular use of sunscreens prevents AKs, the field is a mess," Dr. Williams agreed. "There's a shocking lack of good-quality evidence to inform the debate. That's especially painful to see in a condition as common as this."
Categorizing AKs as carcinoma in situ implies an inevitability of progression that bears no relation to reality. DR. LEIGH